--- linux-2.6.15/kernel/rcupdate.c	2006-01-03 04:21:10.000000000 +0100
+++ linux-2.6.15-edum/kernel/rcupdate.c	2006-01-06 13:32:02.000000000 +0100
@@ -71,14 +71,14 @@
 
 /* Fake initialization required by compiler */
 static DEFINE_PER_CPU(struct tasklet_struct, rcu_tasklet) = {NULL};
-static int maxbatch = 10000;
+static int maxbatch = 100;
 
 #ifndef __HAVE_ARCH_CMPXCHG
 /*
  * We use an array of spinlocks for the rcurefs -- similar to ones in sparc
  * 32 bit atomic_t implementations, and a hash function similar to that
  * for our refcounting needs.
- * Can't help multiprocessors which donot have cmpxchg :(
+ * Can't help multiprocessors which dont have cmpxchg :(
  */
 
 spinlock_t __rcuref_hash[RCUREF_HASH_SIZE] = {
@@ -110,9 +110,19 @@
 	*rdp->nxttail = head;
 	rdp->nxttail = &head->next;
 
-	if (unlikely(++rdp->count > 10000))
-		set_need_resched();
-
+/*
+ * OOM avoidance : If we queued too many items in this queue,
+ *  free the oldest entry (from the donelist only to respect
+ *  RCU constraints)
+ */
+	if (unlikely(++rdp->count > 10000 && (head = rdp->donelist))) {
+		rdp->count--;
+		rdp->donelist = head->next;
+		if (!rdp->donelist)
+			rdp->donetail = &rdp->donelist;
+		local_irq_restore(flags);
+		return head->func(head);
+	}
 	local_irq_restore(flags);
 }
 
@@ -148,12 +158,19 @@
 	rdp = &__get_cpu_var(rcu_bh_data);
 	*rdp->nxttail = head;
 	rdp->nxttail = &head->next;
-	rdp->count++;
 /*
- *  Should we directly call rcu_do_batch() here ?
- *  if (unlikely(rdp->count > 10000))
- *      rcu_do_batch(rdp);
+ * OOM avoidance : If we queued too many items in this queue,
+ *  free the oldest entry (from the donelist only to respect
+ *  RCU constraints)
  */
+	if (unlikely(++rdp->count > 10000 && (head = rdp->donelist))) {
+		rdp->count--;
+		rdp->donelist = head->next;
+		if (!rdp->donelist)
+			rdp->donetail = &rdp->donelist;
+		local_irq_restore(flags);
+		return head->func(head);
+	}
 	local_irq_restore(flags);
 }
 
@@ -208,19 +225,20 @@
  */
 static void rcu_do_batch(struct rcu_data *rdp)
 {
-	struct rcu_head *next, *list;
-	int count = 0;
+	struct rcu_head *next = NULL, *list;
+	int count = maxbatch;
 
 	list = rdp->donelist;
 	while (list) {
-		next = rdp->donelist = list->next;
+		next = list->next;
 		list->func(list);
 		list = next;
 		rdp->count--;
-		if (++count >= maxbatch)
+		if (--count <= 0)
 			break;
 	}
-	if (!rdp->donelist)
+	rdp->donelist = next;
+	if (!next)
 		rdp->donetail = &rdp->donelist;
 	else
 		tasklet_schedule(&per_cpu(rcu_tasklet, rdp->cpu));
@@ -344,11 +362,9 @@
 static void rcu_move_batch(struct rcu_data *this_rdp, struct rcu_head *list,
 				struct rcu_head **tail)
 {
-	local_irq_disable();
 	*this_rdp->nxttail = list;
 	if (list)
 		this_rdp->nxttail = tail;
-	local_irq_enable();
 }
 
 static void __rcu_offline_cpu(struct rcu_data *this_rdp,
@@ -362,9 +378,12 @@
 	if (rcp->cur != rcp->completed)
 		cpu_quiet(rdp->cpu, rcp, rsp);
 	spin_unlock_bh(&rsp->lock);
+	local_irq_disable();
 	rcu_move_batch(this_rdp, rdp->curlist, rdp->curtail);
 	rcu_move_batch(this_rdp, rdp->nxtlist, rdp->nxttail);
-
+	this_rdp->count += rdp->count;
+	rdp->count = 0;
+	local_irq_enable();
 }
 static void rcu_offline_cpu(int cpu)
 {